The engine immobiliser system is designed to prevent the vehicle from being stolen. This system uses a transponder key ecu that stores the key codes of authorized ignition keys. If an attempt is made to start the engine using an unauthorized key, the ecu sends a signal to the ecm to prohibit fuel delivery and ignition, effectively disabling the engine.

The transponder key coil receives this signal, the transponder key amplifier amplifies it, and then the signal is transmitted to the ecu. The ecu matches the key's id code with the vehicle's id code, which was previously registered in the ecu and then communicates the results to the ecm using sfi communication.
Engine immobiliser system
How to proceed with troubleshootingEvap system
Related dtcs
If any evap system dtcs are set, the malfunctioning area can be determined
using the table below.
Notice:
If the reference pressure difference between the first and second checks
is greater than the
specification, all the dtcs relating to the reference pressure (p043e, p ...
Removal
(2005/11-2006/01)
Remove front wheel
Drain automatic transaxle fluid
Drain the automatic transaxle fluid for u140f (see
page ax-147).
Drain the automatic transaxle fluid for u241e (see
page ax-146).
Remove front axle hub nut (see page ah-6)
Disconnect front speed sensor lh (see page
bc-191) ...
Power supply relay failure
Description
If the power steering ecu detects these dtcs, it shuts off the motor relay
circuit (built into the power
steering ecu) and stops power assist.
Inspection procedure
Reconfirm dtc
Check for dtc.
Ok:
dtc is not output.
Replace power steering ecu ...